The objective of this career development award is to provide Dr. Sharon Giordano with the experience and knowledge necessary to become an independent health services researcher in the field of breast cancer. Dr. Giordano, who is a medical oncologist and MPH candidate, will accomplish this goal through a combination of directed reading, seminars, coursework, and mentored research. A highly qualified team of mentors will supervise her training and ensure that she meets her goals. Dr. Giordano will be examining adherence to a standard course of adjuvant treatment among older women with breast cancer using two different approaches: secondary data analyses using the SEER-Medicare database and primary data collection. The specific aims of this proposal are: 1 ) to describe lack of adherence to chemotherapy and radiotherapy in a population-based sample of older women with breast cancer; 2) to determine the effect of specific comorbidities as well as patient, physician, and environmental characteristics on adherence to chemotherapy and radiotherapy; and 3) to prospectively identify factors, including the potentially unrecognized comorbidities of depression and dementia, that affect adherence to therapy in older women with breast cancer. The first two specific aims will be accomplished using the population-based SEER-Medicare database, and the third specific aim through a prospective study. The proposed research will provide important knowledge regarding the patterns and predictors of adherence to adjuvant therapy among older women. In addition, these studies will provide the applicant with expertise in the use of cancer registry data and claims data, in primary data collection, and in data analysis. The proposed studies and career development activities will provide the applicant with the skills to develop into an independent investigator.